Construction machine and projecting object of the same

ABSTRACT

A construction machine and a projecting member thereof are provided which can be manufactured at low cost and restrict deformation of an operator&#39;s cab without impairing visibility in case of tumbling of the construction machine. To this end, there are provided, on a revolving superstructure frame ( 3 ), a work implement ( 30 ) located on the cross-wise mid position of a front part, a counterweight ( 7 ) located at a rear part and an operator&#39;s cab located at either the right or left side of the front part. At least one of the revolving superstructure frame, the work implement and the counterweight is provided with a projecting member ( 31 - 38 ) that projects outward. An operator&#39;s cab space ( 10   a,    20   a ) is kept in an inner position of a vehicle body compared to a virtual plane defined by the at least one projecting member and positions where no projecting members are provided.

This application is a U.S. National Phase Application under 35 USC 371of International Application PCT/JP2004/009271 filed Jun. 24, 2004.

TECHNICAL FIELD

The present invention relates to a construction machine and a projectingmember thereof, the construction machine being structured such that ifthe construction machine overturns (“overturn” is defined herein as aturn through approximately 90 degrees) or tumbles (“tumbling” is definedherein as a turn through approximately 180 degrees or more), anoperator's cab space can be kept to allow the operator to work to repairand recover the construction machine.

BACKGROUND ART

In the field of construction machines, there have been heretoforeproposed a variety of means for protecting the operator from overturn ortumbling of a construction machine by restricting or preventingdeformation of the operator's cab. One example of such means isdisclosed in Japanese Unexamined Published Patent Application No.2000-230255 (First Example). This publication describes, in pages 2 to 3and FIG. 1, a structure for a construction machine in which anoperator's cab is mounted on either the right or left side of arevolving superstructure frame which is mounted on the upper part of thelower traveling structure so as to be freely turnable. This publicationalso describes a supporting structure in which a supporting member isattached to a side face of the revolving superstructure frame on theside of the operator's cab such that if the construction machine turnsover on the operator's cab side, the supporting member holds theconstruction machine in cooperation with the lower traveling structureso as to keep the operator's cab out of touch with the ground. The firstexample provides a means that is inexpensive and easily applicable toordinary construction machines, but suggests no idea for protection ifthe construction machine does not stay in an overturned state but goesinto tumbling.

Another means is disclosed in Japanese Unexamined Published PatentApplication No. 2001-173017 (Second Example). This publicationdescribes, in pages 4 to 5 and FIGS. 1 and 4, a protective structureaccording to which the operator's cab is enclosed by a cab guardconstructed by a portal-shaped frame and the operator's cab is protectedby the cab guard in case of tumbling of the construction machine. Withreference to FIGS. 13 and 14, there will be explained one example ofconstruction machines having a cab protecting structure according to theprior art. When the terms “right” and “left”, are used herein, it shouldbe understood that these terms have reference to the structure of theconstruction machine as it would appear to the operator looking forwardfrom the vehicle (see FIG. 1).

Referring to FIGS. 13 and 14, a hydraulic excavator 80 is constructedsuch that a revolving superstructure frame 82 is mounted on a lowertraveling structure 81 so as to be freely turnable. Mounted on therevolving superstructure frame 82 are a boom 83 for a work implementthat is attached to the cross-wise mid position of the front part of theframe 82; a counterweight 84 that is located in the rear part of theframe 82; and an operator's cab 85 that is located in the left frontpart of the frame 82. A cab guard 90 encloses the operator's cab 85.

In the structure of the hydraulic excavator 80, the provision of the cabguard 90 enclosing the operator's cab 85 has revealed the followingproblem. The cab guard 90 is required to have an extremely strongstructure in order to prevent or restrict deformation of the operator'scab 85 in the event of tumbling of the hydraulic excavator 80. For thisreason, the cab guard 90 becomes extremely costly and an increase in theweight of the operator's cab leads to an increase in the total weight ofthe vehicle, resulting in a decrease in the operability of the vehicle.In addition, the visibility of the operator's cab 85 is interrupted bythe cab guard 90, which leads to decreased work efficiency.

DISCLOSURE OF THE INVENTION

The present invention is directed to overcoming the foregoing problemsand a primary object of the invention is therefore to provide aconstruction machine and a projecting member thereof, which carry outrestriction of deformation of an operator's cab in the event of tumblingof the construction machine without causing increased weight anddecreased visibility and which can be manufactured at low cost.

In accomplishing the above object, there has been provided, inaccordance with a first aspect of the present invention, a constructionmachine comprising: a lower traveling structure; a revolvingsuperstructure frame mounted on the lower traveling structure through aswivel so as to be freely turnable; a work implement mounted on therevolving superstructure frame, being located at a substantiallycross-wise mid position of a front part of the revolving superstructureframe; a counterweight mounted on the revolving superstructure frame,being located at a rear part of the revolving superstructure frame; andan operator's cab mounted on the revolving superstructure frame, beinglocated at either the right or left side of the front part of therevolving superstructure frame,

wherein at least one of the revolving superstructure frame, the workimplement and the counterweight is provided with a projecting memberwhich projects outward, and

wherein an operator's cab space is kept in an inner position of avehicle body compared to a virtual plane, the virtual plane beingdefined by the projecting member disposed on at least one of therevolving superstructure frame, the work implement and the counterweightand positions where no projecting members are provided.

According to a second aspect of the present invention, there is provideda construction machine comprising: a lower traveling structure; arevolving superstructure frame mounted on the lower traveling structurethrough a swivel so as to be freely turnable; a work implement mountedon the revolving superstructure frame, being located at a substantiallycross-wise mid position of a front part of the revolving superstructureframe; a counterweight mounted on the revolving superstructure frame,being located at a rear part of the revolving superstructure frame; andan operator's cab mounted on the revolving superstructure frame, beinglocated at either the right or left side of the front part of therevolving superstructure frame,

wherein an end of the revolving superstructure frame which end islocated on the side of the operator's cab and an upper part of thecounterweight which upper part is opposed to the rear face of theoperator's cab are each provided with a projecting member that projectsupward, and

wherein a virtual plane does not intersect the space of the operator'scab in anywhere, the virtual plane being defined by the projectingmember disposed on the revolving superstructure frame, the projectingmember disposed on the counterweight and the work implement or aprojecting member attached to the work implement so as to project upwardor towards the side of the operator's cab.

According to the first and second aspects, in the event of tumbling, theconstruction machine is supported with the virtual plane being incontact with the ground, which virtual plane is defined by the respectends of the revolving superstructure frame, work implement andcounterweight or the projecting member attached to at least any one ofthe ends of these members. At that time, an operator's cab space wherethe operator can work to repair and recover the construction machine canbe kept in an inner position of the vehicle body than the virtual planeis located. In this case, the projecting member can be manufactured atlower cost and is less heavier in weight, compared to the conventionalcab guard. In addition, since the operator's cab is not enclosed by acab guard, the visibility of the operator's cab can be increased. As aresult, a lightweight structure, which can restrict deformation of theoperator's cab in the event of tumbling of the construction machine, canbe implemented at low production cost while keeping good visibility forthe operator's cab.

In the construction machine according to the first aspect, theprojecting member provided for the counterweight may be an upwardlyprojecting member disposed on an upper part of the counterweight whichupper part faces the rear face of the operator's cab. The upwardlyprojecting member of this structure facilitates keeping of a large spaceas the operator's cab space that is located in the inner position thanthe location of the virtual plane. In addition, since the project areaof the construction machine, which is obtained by projection from above,does not increase, the turn radius of the construction machine does notincrease. Therefore, the invention can be applied to small-sized andmiddle-sized construction machines such as small trail radius hydraulicexcavators without impairing their operability.

According to the invention, there is provided a projecting member for aconstruction machine which has a lower traveling structure; a revolvingsuperstructure frame mounted on the lower traveling structure through aswivel so as to be freely turnable; a work implement mounted on therevolving superstructure frame, being located at a substantiallycross-wise mid position of a front part of the revolving superstructureframe; a counterweight mounted on the revolving superstructure frame,being located at a rear part of the revolving superstructure frame; andan operator's cab disposed on the revolving superstructure frame, beinglocated at either the right or left side of the front part of therevolving superstructure frame,

the projecting member being attached to at least one of the revolvingsuperstructure frame, the work implement and the counterweight such thatthe leading end of the projecting member projects outward,

an operator's cab space being kept in an inner position of a vehiclebody compared to a virtual plane, the virtual plane being defined by theprojecting member attached to at least one of the revolvingsuperstructure frame, the work implement and the counterweight andpositions where no projecting members are provided, and

the projecting member attached to at least one of the revolvingsuperstructure frame, the work implement and the counterweight beingmade of a welded structure, cast part or forged part and having a baseend portion attached to at least any one of the revolving superstructureframe, the work implement and the counterweight.

In the above arrangement, since the projecting member is made of awelded structure, cast part or forged part, it can be universally,easily produced at low cost while the amount of projection such asconfiguration, thickness and length being adjusted according to themachine. Since the projecting member can be attached by bolting orwelding while adjusting its mounting position, the interference with thecomponents of the construction machine can be avoided and the visibilityof the construction machine is not impaired. The projecting member canbe separately formed without affecting the arrangement of any othercomponents of the construction machine. In addition, since theprojecting member is detachable, it can be dismounted according to need,for instance, when the construction machine is put in a delivery vehicleor the like for transportation, so that the transportability of theconstruction machine is not impaired. This enables it to equipconstruction machines of basic specification with the projecting memberas an option and therefore, the projecting member is universally easilyapplicable to a wide range of construction machines from small to largesizes.

To sum up, the invention implements a construction machine and aprojecting member thereof, which provide a light-weight inexpensivestructure for keeping an operator's cab space that allows the operatorto work to repair and recover the construction machine in case oftumbling and which does not impair the visibility of the operator's cab.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a construction machine according to afirst embodiment of the invention.

FIG. 2 is a perspective view of a construction machine according to asecond embodiment of the invention.

FIG. 3 is a perspective view of a construction machine body according tothird and fourth embodiments of the invention.

FIG. 4 is a perspective view of a construction machine body according toa fifth embodiment of the invention.

FIG. 5 is a perspective view of a construction machine body according tosixth and seventh embodiments of the invention.

FIG. 6 is a perspective view of a construction machine according to aneighth embodiment of the invention.

FIG. 7 is a rear view of the construction machine shown in FIG. 6.

FIG. 8 is a perspective view of a construction machine according to aninth embodiment of the invention.

FIG. 9 is an explanatory view illustrating a fundamental part of a boomof a construction machine according to a tenth embodiment of theinvention.

FIG. 10 is an explanatory view illustrating a fundamental part of a boomof a construction machine according to an eleventh embodiment of theinvention.

FIG. 11 is an explanatory view illustrating a fundamental part of a boomof a construction machine according to a twelfth embodiment of theinvention.

FIG. 12 is an explanatory view illustrating a fundamental part of a boomof a construction machine according to a thirteenth embodiment of theinvention.

FIG. 13 is a side view of a hydraulic excavator which is one example ofthe construction machine disclosed in Second Example of the prior art.

FIG. 14 is a partially broken perspective view illustrating afundamental part of the hydraulic excavator shown in FIG. 13.

BEST MODE FOR CARRYING OUT THE INVENTION

Referring now to FIGS. 1 to 12, preferred embodiments of theconstruction machine of the invention will be hereinafter described,taking hydraulic excavators for example.

A first embodiment will be described with reference to FIG. 1. Ahydraulic excavator 1 has a revolving superstructure frame 3 that ismounted on a lower traveling structure 2 through a swivel 16 (see FIG.7) so as to freely turn around upon it. There are provided, on therevolving superstructure frame 3, (i) a boomerang-like boom 4 for a workimplement 30 that is located at a cross-wise mid position of the frontpart of the frame 3; (ii) an engine, a group of control valves, a fueltank, an operating oil tank (these are not shown) and a counterweight 7that are located in the rear part of the frame 3; and (iii) anoperator's cab 10 located at either the right or left side of the frontpart of the frame 3 (in the first embodiment, the operator's cab islocated at the left side).

A projecting member 31 is attached to an end of the front face of therevolving superstructure frame 3 which end is located on the side of theoperator's cab and is a welded structure composed of a base end portion31 b that serves as an attaching part and a vertical supporting portion31 c that is curved from the base end portion 31 b so as to extendupwardly. The vertical supporting portion 31 c extends along the sideface of the operator's cab 10, being spaced therefrom. The base endportion 31 b is detachably attached with a specified number of bolts 31a. The cross-sectional shape of the projecting member 31 is notnecessarily limited to rectangles such as shown in this embodiment butmay be circular. A projecting member 41 is attached to theboomerang-shaped boom 4 at a length-wise mid position that becomes thehighest position when the boom 4 is in an ordinary excavation posture(concretely, the length-wise mid position is the portion of the boom 4that is curved or rounded upward). The projecting member 41 is a weldedstructure sticking out from its base end portions (each serving as anattaching part) in a lateral direction of the operator's cab 10. In thisembodiment, the projecting member 41 is formed such that a U-shapedmember 41 c is welded to the upper parts of front and rear attachingparts 41 b thereby ensuring high rigidity, and the front and rearattaching parts 41 b are detachably attached, by means of a specifiednumber of bolts 41 a, to the side face of the boom 4 which side face islocated on the side of the operator's cab 10.

A projecting member 71 is mounted on the upper face of the counterweight7, being positioned at the end on the same side as the operator's cab10. The projecting member 71 is a welded structure overhanging outward(leftward in this embodiment) from a base end and constructed such thatan opening end of a horizontal member 71 c of U-shaped cross-section iswelded to the upper face of a plate 71 b that serves as an attachingpart. The projecting member 71 is formed such that the horizontal member71 c projects in a lateral direction of the operator's cab 10 and theplate 71 b is detachably bolted to the upper face of the counterweight 7with a specified number of bolts 71 a. The projecting members 31, 41, 71are not necessarily formed from a welded structure but may be made bycasting, forging or the like provided that the projecting members 31,41, 71 have enough strength to sustain the load of the hydraulicexcavator 1 in case of tumbling.

In the above-described structure, the respective leading ends P3, P4, P7of the projecting members 31, 41, 71 define a virtual plane P. Anoperator's cab space 10 a, which is located in an inner position of thevehicle body than the location of the intersecting line P10 of thevirtual plane P and the operator's cab 10, provides a space large enoughto allow the operator to work to repair and recover the constructionmachine 1 within the operator's cab 10 in case of overturning ortumbling. Although three projecting members 31, 41, 71 are provided inthe first embodiment, the number of projecting members is not limited tothis. In other words, at least any one of the three projecting members31, 41, 71 is provided and the virtual plane P is defined by threepoints that are (i) the end of the revolving superstructure frame 3which end is located on the side of the operator's cab 10 or theprojecting member 31; (ii) the end of the boom 4 or the projectingmember 41; and (iii) the end of the counterweight 7 or the projectingmember 71. The virtual plane P should meet the condition in which theoperator's cab space 10 a, which is located in the inner positioncompared to the virtual plane P, is large enough to allow the operatorto work to repair and recover the construction machine 1 within theoperator's cab 10.

The structure of the first embodiment has the following effect. If thehydraulic excavator 1 tumbles, the hydraulic excavator 1 will besupported at three points that are the projecting member 31 provided atthe end of the revolving superstructure frame 3 which end is located onthe side of the operator's cab 10, the projecting member 41 provided atthe end of the boom 4 and the projecting member 71 provided at the endof the counterweight 7. In this case, although the virtual plane Pdefined by these three points (the leading ends P3, P4, P7 of theprojecting members 31, 41, 71 in the first embodiment) comes intocontact with the ground, only an operator's cab space 10 b whichprojects outward from the virtual plane P is deformed so that theoperator's cab space 10 a, which is located in the inner position of thevehicle body 10 compared to the virtual plane P, can be safely kept. Inthis way, deformation of the operator's cab 10 can be limited by theproper configurations and mounting positions of the projecting members31, 41, 71.

Reference is made to FIG. 2 to describe a second embodiment. The secondembodiment is associated with an application of the invention to a smalltrail radius hydraulic excavator 11. The small trail radius hydraulicexcavator 11 is designed such that the turning trajectory T (turningradius=R) of the trail end largely falls within the maximum outer width(lateral length) of the traveling system. The hydraulic excavator 11 isformed such that the revolving superstructure frame 3 is mounted on thelower traveling structure 2 through the swivel so as to be freelyturnable. There are provided, on the revolving superstructure frame 3,(i) the boomerang-like boom 4 disposed at a cross-wise mid position ofthe front part of the frame 3; (ii) the counterweight 7 disposed at therear part of the frame 3; and (iii) an operator's cab 20 disposed ateither the right or left side of the front part of the frame 3 (in thesecond embodiment, the operator's cab is located at the left side).

A projecting member 32 is disposed at an end of the revolvingsuperstructure frame 3 which end is located at a transverse side of theoperator's cab 20 (in the second embodiment, the left side of theoperator's cab 20). The projecting member 32 is located within theturning radius R of the revolving superstructure frame 3. The projectingmember 32 is a welded structure formed such that a supporting member 32c of U-shaped cross-section is welded to a base end member 32 b servingas an attaching part, so as to project upward, and such that the baseend member 32 b is detachably bolted to the revolving superstructureframe 3 with a specified number of bolts 32 a. A projecting member 42,which is composed of an upwardly projecting plate 42 b, is detachablybolted to the boom 4 with a specified number of bolts 42 a. Preferably,the projecting member 42 is disposed in the vicinity of a substantiallylength-wise mid position that becomes the highest position when theboomerang-like boom 4 is in an ordinary excavation posture (concretely,the length-wise mid position is the portion of the boom 4 that is curvedor rounded upward).

A projecting member 72 is attached to an end of the upper face of thecounterweight 7 which end is located on the same side as the operator'scab. The projecting member 72 is formed such that a supporting member 72c produced by bending is welded, in an upright fashion, to two outerperipheral edges of a substantially triangular plate 72 b that serves asan attaching part. The plate 72 b is detachably bolted by use of aspecified number of bolts 72 a, with the supporting member 72 cprojecting upward. It should be noted that the projecting members 32,42, 72 are not necessarily formed from a welded structure but may bemade by casting, forging or the like.

A virtual plane Q is defined by the leading ends Q3, Q4, Q7 of theprojecting members 32, 42, 72. An operator's cab space 20 a, which islocated in an inner position than the location of the intersecting lineQ20 of the virtual plane Q and the operator's cab 20, is large enough toallow the operator to work to repair and recover the constructionmachine 11 within the operator's cab 20 in case of overturning ortumbling. Although three projecting members 32, 42, 72 are provided inthe second embodiment, the number of projecting members is not limitedto this. In other words, at least any one of the three projectingmembers 32, 42, 72 is provided and the virtual plane Q is defined bythree points that are (i) the end of the revolving superstructure frame3 which end is located on the transverse side of the operator's cab 20or the projecting member 32 provided at this end; (ii) the end of theboom 4 or the projecting member 42 provided at this end; and (iii) theend of the counterweight 7 or the projecting member 72 provided at thisend. The virtual plane Q should satisfy the condition in which theoperator's cab space 20 a, which is located in the inner positioncompared to the virtual plane Q, is large enough to allow the operatorto work to repair and recover the construction machine 11 within theoperator's cab 20.

Reference is made to FIG. 3 to describe third and fourth embodiments.The third embodiment is associated with another embodiment of theprojecting member disposed on the transverse side of the operator's cab10. The projecting member of this embodiment is constructed so as toeasily selectively take two positions. One is a position which puts muchvalue on visibility required according to the actual condition of thejob site or on the convenience of the operator getting on and off. Theother position puts much value on keeping of the maximum possible innerspace of the operator's cab 10 in case of tumbling of the constructionmachine. Specifically, a projecting member 33 having an L shape in aside view is made of a welded structure that is composed of a horizontalbase end portion serving as an attaching part and an upright portionextending upward. The base end portion of the projecting member 33 isdetachably bolted to a transverse side of the revolving superstructureframe 3 by use of a specified number of bolts 33 a, such that theleading end of the upright portion projects outwardly from the vehiclebody in an upward direction. In order to enable selective attachment ofthe projecting member 33 between two positions, that is, a frontposition and a rear position (indicated by chain double-dashed line), aplurality of mounting bolt holes are provided in each of the frontposition and the rear position.

According to the third embodiment, the same functions and effects as ofthe first and second embodiments can be achieved. Further, since thethird embodiment makes it possible to easily selectively change themounting position of the projecting member 33 which projects sidewardand upward from the revolving superstructure frame 3, visibility incompliance with the actual condition of the job site and the convenienceof the operator getting on and off can be ensured whereas the maximumpossible operator's cab space can be kept in case of tumbling of theconstruction machine.

The fourth embodiment is associated with another embodiment of theprojecting member disposed at the end of the counterweight 7. Toeliminate an influence upon the transportability of the constructionmachine by avoiding an increase in vehicle width, a projecting member73, which projects rearward from the counterweight 7, is disposed on theupper face of the counterweight 7 on the same side as the operator'scab. The projecting member 73 is a welded structure composed of aplate-like base end member 73 b serving as an attaching part and asupporting member 73 c of U-shaped cross-section which is welded to theupper face of the base end member 73 b, with the opening end of themember 73 c down, such that the supporting member 73 c takes the form ofa rectangular column extending in a horizontal direction. The projectingmember 73 is arranged such that the leading end of the supporting member73 c projects rearward from the counterweight 7 and the base end member73 b is detachably bolted to the upper face of the counterweight 7 witha specified number of bolts 73 a. The projecting member 73 is disposedso as not to stick out from the vehicle body in a widthwise direction.

Reference is made to FIG. 4 to describe a fifth embodiment. According tothe fifth embodiment, a projecting member 34 having an L-shapedcross-section in plan is attached to a corner of the revolvingsuperstructure frame 3 which corner is located on the side of theoperator's cab 10. The projecting member 34 projects upward from therevolving superstructure frame 3 and is detachably bolted, at its baseend that serves as an attaching part, to the corner by use of aspecified number of bolts 34 a. In the fifth embodiment, the leading endP3B of the projecting member 34, an end 7B of the counterweight 7 whichend is located on the same side as the operator's cab 10 and the leadingend P4 (see FIG. 1) of the projecting member 41 of the boom 4 define avirtual plane (not shown). The projecting length of the projectingmember 34 meets the condition in which the operator's cab 10 space,which is located in the inner position compared to the location of theintersecting plane of the virtual plane and the operator's cab 10, islarge enough to allow the operator to work to repair and recover theconstruction machine 1 within the operator's cab 10 in case of tumbling.

With reference to FIG. 5, sixth and seventh embodiments will bedescribed. The sixth and seventh embodiments each provide anotherembodiment of the projecting member that is attached to a side face ofthe revolving superstructure frame 3, projecting outward in a transversedirection, the side face being located on the transverse side of theoperator's cab 20. The side face of the revolving superstructure frame3, which is located on the transverse side of the operator's cab 20, isprovided with screw holes 3 a. In the sixth embodiment, in order that aprojecting member 35 is attached so as to project sideward from the sideface of the revolving superstructure frame 3 on the side of theoperator's cab 20, while restricting an increase in the turning radius Rof the small trail radius hydraulic excavator 11 not to impair theoperability, the projecting member 35, which projects sideward withinthe turning radius R of the revolving superstructure frame 3, is boltedby screwing bolts 35 a into the screw holes 3 a.

In the seventh embodiment, in order to easily attach and detach aprojecting member 36 having a sufficient amount of sideward projectionaccording to need, the projecting member 36, which projects sidewardbeyond the turning radius R of the revolving superstructure frame 3, isbolted by screwing bolts 36 a into the screw holes 3 a. The projectingmembers 35, 36 may be formed of, for instance, a welded structure, castpart or forged part.

With reference to FIGS. 6 and 7, an eighth embodiment will be described.Similarly to FIG. 1, a hydraulic excavator 1A is formed such that therevolving superstructure frame 3 is mounted on the lower travelingstructure 2 through the swivel 16 so as to be freely turnable. Theboomerang-like boom 4 is mounted on the upper face of the front part ofthe revolving superstructure frame 3. The counterweight 7 is mounted onthe upper face of the rear part of the revolving superstructure frame 3.The operator's cab 10 is mounted on the upper face of the left frontpart of the revolving superstructure frame 3.

A projecting member 37 attached to the end of the front face of therevolving superstructure frame 3 which end is located on the side of theoperator's cab is formed from substantially the same welded structure asof the projecting member 31 illustrated in FIG. 1. The vertical lengthof a vertical supporting member 37 c of the projecting member 37 is muchlonger than the vertical supporting member 31 c of the projecting member31. The vertical supporting member 37 c extends along the side face ofthe operator's cab 10, being spaced therefrom. A base end portion 31 bis detachably bolted, using a specified number of bolts 31 a. Similarlyto the projecting member 41 illustrated in FIG. 1, the projecting member41 of the eighth embodiment attached to the position of theboomerang-shaped boom 4 which becomes the highest when the boom 4 is inan ordinary excavation posture is a welded structure projecting from itsbase end portion in a lateral direction of the operator's cab 10.

A projecting member 74 mounted on the counterweight 7 is a weldedstructure that sticks out from its base end portion (in an upwarddirection in the eighth embodiment). The projecting member 74 is formedsuch that a supporting member 74 c having an L shape in top view iswelded, in an upright manner, to the outer peripheries of the left andrear parts of a plate 74 b that serves as an attaching part. The plate74 b is detachably bolted to the upper face of the counterweight 7 bymeans of a specified number of bolts 74 a. The projecting members 37,41, 74 are not necessarily formed from a welded structure but may beformed, for instance, by casting or forging. The projecting members 37,41, 74 should have enough strength to sustain the load of the hydraulicexcavator 1A in case of tumbling.

In the above structure, a virtual plane PA defined by the leading endsP3A, P4A, P7A of the projecting members 37, 41, 74 has no parts thatintersect the operator's cab space 10 a. More concretely, the virtualplane PA does not intersect the operator's cab space 10 a. Therefore,the operator's cab space 10 a is large enough to allow the operator towork to repair and recover the construction machine 1A within theoperator's cab 10 of the construction machine 1A in case of overturningor tumbling. The eighth embodiment uses at least the projecting members37, 74 and the virtual plane PA of the eighth embodiment is defined bythree points that are (i) the leading end P3A of the projecting member37, (ii) the leading end P7A of the projecting member 74 and (iii) theend of the boom 4 or the leading end P4A of the projecting member 41disposed at this end. The end of the boom 4 mentioned above is aposition where the projecting member 41 is not provided and correspondsto the mounting position for the projecting member 41 such as shown inFIG. 6.

With reference to FIG. 8, a ninth embodiment will be described.Similarly to the second embodiment, the ninth embodiment is associatedwith an example in which the invention is applied to a small trailradius hydraulic excavator 11A. The hydraulic excavator 11A has aprojecting member 38 that is attached to an end of the revolvingsuperstructure frame 3 which end is located on the left side of theoperator's cab 20 in a rear view of the vehicle body and located withinthe turning radius R of the revolving superstructure frame 3. Theprojecting member 38 is a welded structure having substantially the sameconstruction as of the projecting member 32 illustrated in FIG. 2. Thevertical length of a supporting member 38 c of the projecting member 38is longer than the supporting member 32 c of the projecting member 32.The boomerang-like boom 4 is provided with the projecting member 42which is detachably attached thereto so as to project more upwardly thanthe projecting member 42 illustrated in FIG. 2. Like the foregoingembodiment, the projecting member 42 is preferably disposed in thevicinity of a substantially length-wise mid position that becomes thehighest position when the boom 4 is in an ordinary excavation posture. Aprojecting member 75 is attached to an end of the upper face of thecounterweight 7 which end is on the same side as the operator's cab 20(the projecting member 75 is located at a position opposed to the rearface of the operator's cab 20). The projecting member 75 is a weldedstructure substantially similarly constructed as the projecting member72 illustrated in FIG. 2. The vertical length of a supporting member 75c of the projecting member 75 is longer than that of the supportingmember 72 c of the projecting member 72. The projecting members 38, 42,75 are not limited to a welded structure but may be formed by casting,forging etc.

A virtual plane QA defined by the leading ends Q3A, Q4A, Q7A of theprojecting members 38, 42, 75 has no parts that intersect the operator'scab space 20 a of the operator's cab 20 (see the virtual plane PA shownin FIG. 7). Therefore, the operator's cab space 20 a is large enough toallow the operator to work to repair and recover the overturned ortumbled construction machine 11A within the operator's cab 20 of theconstruction machine 11A. The ninth embodiment uses at least theprojecting members 38, 75 and the virtual plane QA of the ninthembodiment is defined by three points that are (i) the leading end Q3Aof the projecting member 38, (ii) the leading end Q7A of the projectingmember 75 and (iii) the side edge of the boom 4 or the leading end Q4Aof the projecting member 42 disposed at this side edge. The side edge ofthe boom 4 just mentioned above is a position of the boom 4 where theprojecting member 42 is not provided and corresponds to the mountingposition for the projecting member 42 such as shown in FIG. 8.

Reference is made to FIGS. 9 to 12 to describe tenth to thirteenthembodiments each providing another example of the projecting memberattached to the end of the boom 4. In the tenth embodiment, a part of anupper face plate 4 a of the boom 4 sticks out in a lateral direction ofthe operator's cab as shown in FIG. 9, thereby providing the boom 4 witha projecting member 43 that projects sideward. The projecting member 43is preferably disposed in the vicinity of a substantially length-wisemid position that becomes the highest position when the boom 4 is in anordinary excavation posture (concretely, the length-wise mid position isthe portion of the boom 4 that is curved or rounded upward).

In the eleventh embodiment, the boom 4 is provided, as shown in FIG. 10,with a pin 6 for attaching a lifting/lowering hydraulic cylinder 5. Thepin 6 is attached so as to project in a lateral direction of theoperator's cab more than a retainer 6 a for preventing the hydrauliccylinder 5 from coming off. The pin 6 constitutes a projecting member 44that projects sideward.

In the twelfth embodiment, a projecting member 4 b formed by arcuatelybending a pipe is welded, as shown in FIG. 11, to the upper face of theboom 4. The projecting member 4 b is attached to an end that is on theside of the operator's cab and behind the position curved or roundedupward. Thereby, a projecting member 45 is formed which projects upwardor rearward from the boom 4. The projecting member 4 b is notnecessarily limited to the shape and material described above, but maybe formed from a rectangular pipe, round bar or the like. In addition,the mounting position is not limited to the upper face of the boom 4.The projecting member 45 may be welded to a side face of the boom 4.Further, the means for connecting the boom 4 to the projecting member 45is not limited to welding but may be attachment by use of bolts (notshown) or the like.

In the thirteenth embodiment, a right and left pair of plates 4 c areattached, as shown in FIG. 12, to the upper face of the boom 4 so as toface each other in an upright condition. The front parts of the plates 4c are used as a bracket 4 d for attaching a hydraulic cylinder 9 fordriving an arm 8 (see FIGS. 1, 2, 6, 8), whereas the rear parts are usedas projecting members 46 that project upward from the boom 4.

With the structures of the tenth to thirteenth embodiments, the samefunctions and effects as of the first to fourth embodiments can beattained. In addition, the projecting members 43, 44 that projectsideward from the boom 4 and the projecting members 45, 46 that projectupward can be manufactured as lightweight members at low cost.

In the structures of the first to thirteenth embodiments, the projectingmembers 31 to 38 disposed at the end of the revolving superstructureframe 3, the projecting members 41 to 46 disposed at the end of the boom4 and the projecting members 71 to 75 disposed at the end of thecounterweight 7 may be selectively employed in a desired combination.The mounting positions for these projecting members may be selected fromthree positions, i.e., the revolving superstructure frame 3, the boom 4and the counterweight 7. Although the projecting members 31 to 38,projecting members 41 to 42 and projecting members 71 to 75 aredetachably mounted in the above description, these projecting membersare not limited to this but may be integrally formed with the revolvingsuperstructure frame 3, the boom 4 and the counterweight 7 respectively,by means of welding, casting or the like.

As a result, in a construction machine wherein a revolvingsuperstructure frame is mounted on a lower traveling structure through aswivel so as to be freely turnable and wherein the upper face of therevolving superstructure frame is provided with a boom mounted on itsfront part, a counterweight mounted on its rear part and an operator'scab mounted on either the right or left side of the front part, it ispossible to restrict deformation of the operator's cab by use ofprojecting members of simple configuration in case of tumbling of theconstruction machine. This enables it to arrange and produce alightweight, low-cost protective structure for the operator's cab, whichkeeps an operator's cab space for the operator to work to repair andrecover the tumbled construction machine. In addition, this structure iseasy to apply to a variety of small-sized and middle-sized constructionmachines so that it has a wide range of applications.

While the embodiments of the construction machine of the invention havebeen described hereinabove in the context of a hydraulic excavator, theapplication of the invention is not necessarily limited to a hydraulicexcavator but the invention may be universally applicable to other typesof construction machines in the same way as described earlier. Where theinvention is applied to other types of construction machines, the samefunctions and effects as of the above description can be attained.

INDUSTRIAL APPLICABILITY

The invention provides a useful construction machine and projectingmember thereof which can be manufactured at low production cost andcarry out restriction of deformation of the operator's cab withoutimpairing visibility in the event of tumbling of the constructionmachine.

1. A construction machine comprising: a lower traveling structure; arevolving superstructure frame mounted on the lower traveling structurevia a swivel so as to be freely turnable; a work implement, whichcomprises a boomerang-shaped boom, mounted on the revolvingsuperstructure frame substantially at a cross-wise middle position of afront part of the revolving superstructure frame; a counterweightmounted on the revolving superstructure frame at a rear part of therevolving superstructure frame; and an operator's cab mounted on therevolving superstructure frame at one of a right side and a left side ofthe front part of the revolving superstructure frame, a first projectingmember which projects upward, and which is attached to a front face ofthe revolving superstructure frame at a same side of the revolvingsuperstructure frame as the operator's cab; a second projecting memberwhich is provided at a vertex of the boomerang shape of the boom; athird projecting member which is provided on an upper face of thecounterweight at a same side of the construction vehicle as theoperator's cab; wherein a virtual plane is defined by three points,which are provided at the first projecting member, the second projectingmember, and the third projecting member, respectively; and wherein anoperator's cab space is positioned closer to a body of the constructionmachine than the virtual plane.